Egg Freezing: Fertility, Math, and Me

The Journey Begins

Like many people, I’ve spent much of my adult life trying not to get pregnant. As time passed and I still hadn’t met “the one,” I decided to look into cryopreservation in my mid-30’s.

At the time, I’d heard that technology for egg freezing versus embryo freezing was “not quite there.” When I met with two top clinics and asked how many babies had been born from eggs frozen there, the answer was startlingly low: 15 at one and 35 at the other (I met with the second clinic three years after meeting with the first). This, combined with my historic sensitivity to the pill and reluctance to take hormones, led me to take a pass at that point.

And so life happens. I had a relationship and didn’t want to interrupt it with this process, then a job change, then another relationship, then some family matters. On the other side of this, I was in my early 40’s with older eggs but, from what I understood, the benefit of access to more advanced cryopreservation methods. I wanted to have children, but not right then, on my own, and ideally with someone I was in a relationship with. My time had come.

How Much is Enough

After a couple of rounds I had 20 mature eggs (the immature eggs don’t count). I had been told two different stats that gave me comfort in this number, but also confusion as to whether I should continue just to be safe: (1) it’s roughly a 10:1 ratio of eggs to live babies and (2) at my age, about 25% of embryos are genetically normal. I scheduled a call with my doctor to see whether my stash was enough to qualify as insurance (and maybe, if I’m really lucky, for more than one). The conversation went roughly like this.

Dr: Hi. Congratulations! This was a great outcome and I’m really pleased with your result.

Me: Fantastic! Thank you! So…do you think this is enough eggs for one baby or might it be enough for two?

Dr: This gives you about a 40% chance of having one healthy baby.

Me: Huh?

The doctor then walked me through factors that I hadn’t taken into account. There are a couple of points where you lose eggs along the way before genetic testing: thawing (the process has improved a lot but there may still be some slippage), fertilization (70-80% typical success with ICSI), and maturation (50% of fertilized eggs typically reach blastocyst stage by day 6). You combine those ratios with a 25% genetically normal percentage at my age and a 50% probability that a woman carries a child to term without miscarriage and…I felt a lot less comfortable with my insurance policy.

I asked the doctor whether another round, or another two rounds, would get me a coin toss. He said it is tough to say. I asked whether I should fertilize a round to see what my math looks like. He said it would only give me color on that particular batch of eggs, not generally.

I decided to get a second opinion.

Differing Protocols

What followed was educational.

I went to four doctors in three cities and did two more rounds, this time with the intention of fertilizing my eggs. The thinking was this would give me a clear picture of where I stood and everyone agreed that fertilizing made sense. That would be the only thing everyone agreed on.

Some doctors thought the start date should be day two or three; others said it didn’t matter. Some said being on the pill for two to four weeks would amplify egg production during the cycle; others said you should never suppress ovulation in someone my age. The doses prescribed of the overlapping drugs varied wildly. Medication either had to be given at two different times or all at once. I could have limited coffee and alcohol during stimulation and do moderate exercise the first few days, or absolutely none of the above.

As to the results…each cycle produced roughly the same number of eggs, but a totally different number of embryos at the end of the funnel. In the first cycles, very few of my eggs fertilized and only one grew to blastocyst. In the later cycles, most of my eggs fertilized and a decent number grew to blastocyst.
These rounds were done two months apart (same me). Both clinics are top rated in the country.

Shots on Goal

My biggest takeaway is that it is imperative to be an educated consumer: to assess whether your insurance policy actually has you reasonably covered and to evaluate whether the medical protocol you’re prescribed makes sense for your body. How many shots on goal do you need to win, and what’s the right way to set up the play.

The process is labor intensive, expensive, confusing and sometimes emotionally hard. However, I still am feeling grateful that science gives us the ability to enhance our natural timeline in this way. To what end, I’ll know soon enough.

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Expert's Perspective

Jacque Cohen, PhD

Laboratory Director at Walter Reed National Military Medical Center (NIH)